Calculating multileg one-loop processes. The case of gg -> t bar_t+gg

Abstract

This study is targeted to the NLO corrections of multileg processes, very important for the LHC. Starting from the construction of Feynman diagrams, the analytical reduction of general one-loop integrals to scalar master ones, the calculation of color structures, manipulation of spinor lines and other amplitude constituents and finally phase space point selection are obtained by use of a program producing Fortran code for numerical calculation of one-loop corrections for processes like gg -> t bar_t+gg.

Comments: Talk given at 13th International Workshop on Advanced Computing and Analysis Techniques in Physics Research, ACAT2010, February 22-27, 2010, Jaipur, India. References added